遮阴对三种毛茛科植物光合特性的影响及耐阴性评价

Effects of shading on photosynthetic characteristics and shade-tolerance evaluation of three Ranunculaceae plants

关键词:  毛茛科, 遮阴, 光合特性, 耐阴性, 评价

Key words:  Ranunculaceae, shading, photosynthetic characteristics, shade-tolerance, evaluation

摘要:

为探究毛茛、华东唐松草和卵瓣还亮草3种毛茛科植物对不同光环境的响应机制,该文设置5个光梯度的处理水平(0%、30%、50%、70%和90%的遮阴程度),测定3种植物的光合指标,研究不同遮阴处理对其光合特性的影响及耐阴性评价。结果表明:随遮阴程度逐渐增加,(1)3种植物的叶绿素a、叶绿素b、叶绿素(a+b)和类胡萝卜素含量呈上升趋势,而叶绿素a/b含量则呈下降趋势。(2)3种植物的表观量子效率(AQY)均先上升后下降; 毛茛和卵瓣还亮草最大净光合速率(P_max)呈先升后降的变化趋势,华东唐松草的P_max呈下降趋势; 3种植物的光饱和点(LSP)、光补偿点(LCP)、暗呼吸速率(R_d)均呈逐渐降低趋势。(3)3种植物的初始荧光(F_o)先下降后上升,而最大荧光(F_m)、可变荧光(F_v)、PSⅡ最大光化学效率(F_v/F_m)和PSⅡ潜在活性(F_v/F_o)值则先上升后下降; 热耗散的量子比率(φDo)、单位反应中心耗散掉的能量(DIo/RC)先下降后上升,而电子传递量子产额(φEo)、单位反应中心吸收的光能(ABS/RC)、单位反映中心所捕获的光能(TRo/RC)、单位反映中心用于传递电子的能量(ETo/RC)、光合性能指数(PIabs)及综合性能指数(PItotal)均先上升后下降。(4)利用主成分分析、隶属函数法等分析方法对20个单指标进行综合分析,3种植物的耐阴性排序为华东唐松草>卵瓣还亮草>毛茛。综上结果认为,3种毛茛科植物对光照有着不同的适应能力,该结论为毛茛科植物在园林绿化的应用中提供了依据。

Abstract:

In order to investigate the response mechanism of Ranunculus japonicus, Thalictrum fortunei and Delphinium anthriscifolium var. savatieri in different light environments, five shade treatment levels(0%, 30%, 50%, 70% and 90% shade degrees)were set in this study, the photosynthetic indexes of the three plants were determined, and the effects of different shade treatments on their photosynthetic characteristics and shade-tolerance evaluation were studied. The results were as follows: with the increase of shading degree,(1)The contents of chlorophyll a, chlorophyll b, chlorophyll(a+b)and carotenoid increased, while the content of chlorophyll a/b decreased.(2)The apparent quantum yield(AQY)of the three plants increased first and then decreased; the maximum net photosynthetic rate(P_max)of Ranunculus japonicus and Delphinium anthriscifolium var. savatieri showed a trend of first rising and then decreasing, while the P_max of Thalictrum fortunei showed a decreasing trend. The light saturation point(LSP), light compensation point(LCP)and dark respiration rate(R_d)of the three plants decreased gradually.(3)The original fluorescence(F_o)decreased first and then increased, while the maximum fluorescence(F_m), variable fluorescence(F_v), maximum photochemical efficiency of PS Ⅱ(F_v/F_m)and potential activity of PS Ⅱ(F_v/F_o)values increased first and then decreased; the quantum ratio of heat dissipation(φDo)and the energy dissipated per unit reaction center(DIo/RC)decreased first and then increased, while electron transport quantum yield(φEo), light energy absorbed per unit reaction center(ABS/RC), light energy captured per unit reaction center(TRo/RC), energy used to transfer electrons per unit reaction center(ETo/RC), photosynthetic performance index(PIabs)and comprehensive performance index(PItotal)increased first and then decreased.(4)Comprehensive analysis on 20 single indicators by using analysis methods such as principal component analysis and membership function method showed that the shade-tolerance of the three plants ranked as Thalictrum fortunei > Delphinium anthriscifolium var. savatieri > R. japonicus. In conclusion, the three species have different adaptability to light, which provides a reference for the application of Ranunculaceae plants in landscaping.